How to Write a Sample letter

This is the letter to convey my apology to business associate for not including his name in the invitation. First of all I should regret for my behaviour and I regret for it in a very precise manner. As you know in our company we are celebrating the annual day of our company. Since you are the sleeping partner and moreover since you are a govt employee you are not supposed to run any other company. That’s why I didn’t include your name. Let the things happened be happened. Now am here to ask for apology. I request you accept my apology and let me to work again here. I swear I will not include in this kind of mistakes one more time. I swear this with confidence on me.